| 摘要 |
PROBLEM TO BE SOLVED: To provide a booster of negative pressure type which shorten a reponse time to operation easily and at low cost. SOLUTION: A seat part 143 for controlling negative pressure and a seat part 241 for controlling the atmosphere are disposed at shifted positions in an axial direction. A control valve 27 urged by a spring 26 has a seal part 272 for controlling negative pressure on one end thereof and a seal part for controlling the atmosphere on the inner peripheral part at shifted positions in an axial direction and it is provided with seal members 274, 275 hermetically engaging with the inner peripheral part of a power piston 14 on the outer peripheral part, a plurality of communicating passageways 276 allowing a variable pressure room Ra2 to communicate with a constant pressure room Ra1, and a stopper 277. The power piston 14 has a plurality of communicating passage 142 which are near the communicating passage 276 and allow the variable pressure room Ra2 to communicate with a constant pressure room Ra1 and a hole 43 which is used for engaging with the stopper 277 and allows the variable pressure room Ra2 to communicate with a constant pressure room Ra1. |
